Carbon-based materials are primarily used as anode active materials for a lithium secondary battery. However, the anode composed of carbon material exhibits a maximum theoretical capacity of only 372 mAh/g (844 mAh/cc) thus limiting increase of capacity thereof. Lithium metals, studied for use as the anode material, have a high energy density and thus may realize high capacity, but have problems associated with safety concerns due to growth of dendrites and a shortened charge/discharge cycle life as the battery is repeatedly charged/discharged.
Further, a number of studies and suggestions have been proposed as to a lithium alloy serving as a material exhibiting high capacity and capable of substituting for the lithium metal. Silicon (Si) reversibly occludes and releases lithium through reaction therewith, and has a maximum theoretical capacity of about 4020 mAh/g materials and thereby is promising as a high capacity anode material. However, upon charging/discharging the battery, Si is cracked due to changes in volume resulting from reaction with the lithium, and particles of Si active material are destroyed. For this reason, as charge/discharge cycles are repeated, the capacity of the battery is sharply lowered and the charge/discharge cycle life thereof is reduced.
In order to overcome these problems, there have been studies and suggestions on a composite active material configuration composed of an active phase which reacts with lithium and an inactive phase which does not react with lithium, but there was no suggestion on the anode material for a variety of non-aqueous electrolyte-based secondary battery having composite compound composition which can exert optimal performance of the material used and a method for preparing the same as in the anode material and method for preparing the same in accordance with the present invention.